The present invention relates to substituted benzamide compounds, to a process for their preparation, to medicaments comprising these compounds, and to the use of substituted benzamide compounds in the preparation of medicaments.
Unlike the constitutive expression of the bradykinin 2 receptor (B2R), the bradykinin 1 receptor (B1R) is not expressed or is expressed only weakly in most tissues. However, the expression of B1R in various cells is inducible. For example, following inflammation reactions there is a rapid and pronounced induction of B1R in neuronal cells but also in various peripheral cells such as fibroblasts, endothelial cells, granulocytes, macrophages and lymphocytes. Accordingly, in the course of inflammation reactions there is a switch from B2R to B1R dominance in the cells that are involved. The cytokines interleukin-1 (IL-1) and tumour necrosis factor alpha (TNFα) play a substantial part in this B1R up-regulation (Passos et al., J. Immunol. 2004, 172, 1839-1847). Following activation with specific ligands, B1R-expressing cells are then themselves able to secrete inflammation-promoting cytokines such as IL-6 and IL-8 (Hayashi et al., Eur. Respir. J. 2000, 16, 452-458). This results in the immigration of further inflammatory cells, for example neutrophilic granulocytes (Pesquero et al., PNAS 2000, 97, 8140-8145). By way of these mechanisms, the bradykinin B1R system can contribute to the chronification of diseases. This is proved by a large number of animal experiments (overviews in Leeb-Lundberg et al., Pharmacol. Rev. 2005, 57, 27-77 and Pesquero et al., Biol. Chem. 2006, 387, 119-126). In humans too, enhanced expression of B1R is found, for example, in enterocytes and macrophages in the affected tissue of patients with inflammatory intestinal diseases (Stadnicki et al., Am. J. Physiol. Gastrointest. Liver Physiol. 2005, 289, G361-366) or in T-lymphocytes of patients with multiple sclerosis (Prat et al., Neurology, 1999; 53, 2087-2092), or activation of the bradykinin B2R-B1R system is found in the course of infections with Staphylococcus aureus (Bengtson et al., Blood 2006, 108, 2055-2063). Infections with Staphylococcus aureus are responsible for symptoms such as superficial skin infections to septic shock.
Due to the described pathophysiological relationships there is a great therapeutic potential for the use of B1R antagonists in acute and, in particular, chronic inflammatory diseases. These include respiratory diseases (Asthma bronchiale, allergies, COPD/chronic-obstructive pulmonary disease, cystic fibrosis, etc.), inflammatory intestinal diseases (ulcerative colitis, CD/Crohn's disease, etc.), neurological diseases (multiple sclerosis, neurodegeneration, etc.), inflammations of the skin (atopic dermatitis, psoriasis, bacterial infections, etc.) and mucosa (Behcet's disease, pelvitis, prostatitis, etc.), rheumatic diseases (rheumatoid arthritis, osteoarthritis, etc.), septic shock and reperfusion syndrome (following heart attack, stroke).
In addition, the bradykinin (receptor) system is also involved in regulating angiogenesis (potential as an angiogenesis inhibitor in cancer and macular degeneration of the eye), and B1R knockout mice are protected against the induction of excess weight as a result of a particularly high-fat diet (Pesquero et al., Biol. Chem. 2006, 387, 119-126). B1R antagonists are therefore suitable also for the treatment of obesity.
B1R antagonists are suitable in particular for the treatment of pain, in particular inflammatory pain and neuropathic pain (Calixto et al., Br. J. Pharmacol. 2004, 1-16), in particular diabetic neuropathy (Gabra et al., Biol. Chem. 2006, 387, 127-143). They are also suitable for the treatment of migraine.
In the development of B1R modulators there is the problem, however, that the human and the rat B1R receptor differ so widely that many compounds which are good B1R modulators on the human receptor have only a poor or no affinity for the rat receptor. This makes animal pharmacology studies considerably more difficult, since many studies are usually conducted on the rat. However, if there is no activity on the rat receptor, neither action nor side-effect can be investigated on the rat. This has already meant that transgenic animals with human B1 receptors have been produced for animal pharmacology studies (Hess et al., Biol. Chem. 2006; 387(2):195-201). Working with transgenic animals is more expensive, however, than working with the unmodified animals.
International patent application nos. WO 2008/040492 and WO 2008/046573 describe compounds that exhibit antagonistic activity both on the human B1 receptor and on the B1 receptor of the rat in in vitro assays.
International patent application nos. WO 2007/140383 and WO 2007/101007 describe compounds that exhibit an antagonistic activity on the macaque B1 receptor in in vitro assays. Experimental data relating to activity on the human B1 receptor or on the B1 receptor of the rat are not disclosed.
There is a continued need for novel B1R modulators, B1R modulators that bind both to the rat receptor and to the human receptor offering particular advantages.